Re: [TCML] Why air-core?

[Ed Phillips <evp@xxxxxxxxxxx>]

I'm not sure there IS any 'official' definition of a Tesla coil.  
Teslaused iron cores in some of his early experiments but not in later 
ones..  Resonant rise and transfer of energy from a low voltage source 
to a high voltage output by using it fits the definition I see people 
here using.  The air core transformer is very easy to build and gives 
satisfying results so guess it could be considered the de facto standard 
but there are other configurations which work.

oklahomacoiler@xxxxxxxxx wrote:

> Isn't a Tesla Coil defined as an air core resonant rise transformer though?
> Kevin.
>
>
> Sent from my HTC Inspire^(TM) 4G on AT&T
>
> ----- Reply message -----
> From: "mike hollingsworth" <megavolts_61@xxxxxxxxx>
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Subject: [TCML] Why air-core?
> Date: Sat, Oct 1, 2011 9:50 pm
>
>
> I have a x-ray transformer that puts out around 40kv at 20kHz and about 2.5kVA.  This little monster is about 4.5 inches in diameter by four inches tall,  so it is conceivable that a TC could be made with a core of such material.  it would have to be a fairly long, skinny core and most likely immersed in oil to work, but if one designed a coil to operate at that low a frequency,  I don't see why it couldn't be done.
> Mike
>
>
>
> ________________________________
> From: Eric Goodchild <ericgoodchild@xxxxxxxxx>
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Sent: Saturday, October 1, 2011 8:22 PM
> Subject: Re: [TCML] Why air-core?
>
> On 10/1/2011 7:16 PM, Gary Lau wrote:
>  
>
> > I was asked a fundamental question about Tesla coils recently.  I _think_ I
> > knew the answer, but I'd like to check.
> >
> > A Tesla coils is strictly an air-core transformer.  I said that steel or
> > ferrite cores are not used because:
> > 1) Core saturation would be likely
> > 2) The conductive core would degrade the high voltage standoff capability
> > 3) The coupling with a cored design would be too high
> >
> > Did I get it right?
> >
> > Thanks, Gary Lau
> > MA, USA
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> > http://www.pupman.com/mailman/listinfo/tesla
> >    
> I strongly agree with 1, core saturation would defiantly be a problem, particularly with a DRSSTC. At hundreds of amps peak you would need an air gap so big you may as well call it air core... This is how I figure it.
>
> Another thing I may add to that list  is that the size of the core would likely be massive if you could manage to get it to not saturate. A core of this size would be very unwieldy and heavy.
>
> 2 and 3 almost make logical sense to me.
>
> Eric
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